How NASA plans to bring back samples from Mars

WASHINGTON: NASA has revealed how it plans to bring back Martian samples to Earth for the first time with the help of its next rover mission to the Red Planet, Mars 2020.

After landing on Mars, a drill will capture rock cores, while a caching system with a miniature robotic arm will seal up these samples. Then, they will be deposited on the Martian surface for possible pickup by a future mission, NASA said.

"Whether life ever existed beyond Earth is one of the grand questions humans seek to answer," said Ken Farley of NASA's Jet Propulsion Laboratory in Pasadena, California.

"What we learn from the samples collected during this mission has the potential to address whether we're alone in the universe," Farley said.

Mars 2020 relies heavily on the system designs and spare hardware previously created for Mars Science Laboratory's Curiosity rover, which landed in 2012.

Despite its similarities to Mars Science Laboratory, the new mission has very different goals - it will seek signs of ancient life by studying the terrain that is now inhospitable, but once held flowing rivers and lakes, more than 3.5 billion years ago.

To achieve these new goals, the rover has a suite of cutting-edge science instruments.

It will seek out biosignatures on a microbial scale.

An X-ray spectrometer will target spots as small as a grain of table salt, while an ultraviolet laser will detect the "glow" from excited rings of carbon atoms.

A ground-penetrating radar will look under the surface of Mars, mapping layers of rock, water and ice up to 10 metres deep, depending on the material.

The rover is getting some upgraded Curiosity hardware, including colour cameras, a zoom lens and a laser that can vaporise rocks and soil to analyse their chemistry, NASA said.

The mission will also undertake a marathon sample hunt.

The rover team will try to drill at least 20 rock cores, and possibly as many as 30 or 40, for possible future return to Earth, NASA said.

Site selection has been another milestone for the mission. In February, the science community narrowed the list of potential landing sites from eight to three.

All three sites have rich geology and may potentially harbour signs of past microbial life. But a final landing site decision is still more than a year away.

"In the coming years, the 2020 science team will be weighing the advantages and disadvantages of each of these sites," Farley said.

"It is by far the most important decision we have ahead of us," Farley said.